In the days before Secret Service, President Lincoln often walked around Washington City alone. When his wife complained about him walking alone through parts of the city with names such as “Murderer’s Bay,” he agreed to arm himself.
When he remembered it, he carried a thick oak stick.
The ferrule — the part of the stick that came in contact with the ground — was an iron bolt from the Merrimac. The head was a bolt from the Monitor.
He almost never carried it.
He told reporter Noah Brooks, “Mother has got a notion in her head that I shall be assassinated. And, to please her, I take a cane when I go over to the War Department at night, when I don’t forget it.”
Source: “A. Lincoln: His Last Hours” by W. Emerson Reck